[Drakelist] AF output tube in R4A
Is the AF output tube in the R4A swappable with the same tube in the 2-B? I Googled but it is not clear. Btw, what is a beam pentode or tetrode? Is 6EH5 in V7 one of these? ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AF output tube in R4A
No. The 2-B uses the 6AQ5 and the R-4 Series all use the 6EH5. The 6EH5 is not a Beam Power Pentode, the 6AQ5 is. The third 'grid' in a Pentode can be either a spiral wrapped grid like the other two, OR it can be 'plates' that 'focuses' the electron beam more fully on the Plate. Primary result is greater power capability as a result of 'all' Cathode current reaching the Plate. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Neil M Califano wrote: Is the AF output tube in the R4A swappable with the same tube in the 2-B? I Googled but it is not clear. Btw, what is a beam pentode or tetrode? Is 6EH5 in V7 one of these? ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AF output tube in R4A
FWIW, there is a good illustration and explanation of beam power tubes in all of the old RCA tube handbooks. In fact, these books have an excellent primer on tubes and their applications in the front. Well and clearly written. Note: do people on this list prefer top replies or bottom? I got a private e-mail asking me to change to top posting so I am trying it. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com - Original Message - From: Garey Barrell k4...@mindspring.com To: drakelist Drakelist@zerobeat.net Sent: Thursday, August 25, 2011 2:30 PM Subject: Re: [Drakelist] AF output tube in R4A No. The 2-B uses the 6AQ5 and the R-4 Series all use the 6EH5. The 6EH5 is not a Beam Power Pentode, the 6AQ5 is. The third 'grid' in a Pentode can be either a spiral wrapped grid like the other two, OR it can be 'plates' that 'focuses' the electron beam more fully on the Plate. Primary result is greater power capability as a result of 'all' Cathode current reaching the Plate. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Neil M Califano wrote: Is the AF output tube in the R4A swappable with the same tube in the 2-B? I Googled but it is not clear. Btw, what is a beam pentode or tetrode? Is 6EH5 in V7 one of these? ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AF output tube in R4A
On Thu, 25 Aug 2011 16:34:03 -0700, Richard Knoppow wrote: Note: do people on this list prefer top replies or bottom? I got a private e-mail asking me to change to top posting so I am trying it. It varies. In the dialup BBS scene where I cut my online teeth, bottom posting was the standard. It also follows the flow of the conversation. Top posting is lazinesss in some cases, but seems to have become the preferred method in the business world because it creates a paper trail. Whatever. You will never get any group of two or more people to agree on using one method or the other. I just use what seems appropriate for the individual message, depending on content and length of reply, and whether interleaving makes sense. More important IMO is I REALLY wish people would learn to trim replies and use apostrophes correctly 73 -Jim (don't even get me started on reading comprehension) -- A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail? ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AF output tube in R4A
The 6AQ5 is designed to work with 250V on the plates, and was operating at reduced efficiency in the 2-B. By the time the 4 Series was designed, the 6EH5 was introduced, and was designed for 150V plate supply. A tube amplifier Class operated A sounds so much smoother than any solid state discrete or IC audio amplifier. Combine that with the low distortion of the L/C IF filters, and you have a receiver that you can listen to all day without fatigue. By comparison, a receiver with hard edged crystal filters with their phase distortion and group delay, fed through a solid-state amp, and you're good for a headache in an hour... 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Neil M Califano wrote: Why didn't Drake use the 6AQ5 in the R4A? I read the tube performs as well as much larger ones. Also, could the 6AQ5 account for the pleasant tone of the 2-B? --- On Thu, 8/25/11, Garey Barrellk4...@mindspring.com wrote: From: Garey Barrellk4...@mindspring.com Subject: Re: [Drakelist] AF output tube in R4A To: drakelistDrakelist@zerobeat.net Date: Thursday, August 25, 2011, 5:30 PM No. The 2-B uses the 6AQ5 and the R-4 Series all use the 6EH5. The 6EH5 is not a Beam Power Pentode, the 6AQ5 is. The third 'grid' in a Pentode can be either a spiral wrapped grid like the other two, OR it can be 'plates' that 'focuses' the electron beam more fully on the Plate. Primary result is greater power capability as a result of 'all' Cathode current reaching the Plate. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Neil M Califano wrote: Is the AF output tube in the R4A swappable with the same tube in the 2-B? I Googled but it is not clear. Btw, what is a beam pentode or tetrode? Is 6EH5 in V7 one of these? ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AF output tube in R4A
Top posting preferred. ~Damon Raphael, W7MD On 08/25/2011 04:34 PM, Richard Knoppow wrote: FWIW, there is a good illustration and explanation of beam power tubes in all of the old RCA tube handbooks. In fact, these books have an excellent primer on tubes and their applications in the front. Well and clearly written. Note: do people on this list prefer top replies or bottom? I got a private e-mail asking me to change to top posting so I am trying it. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] AF output tube in R4A
On Thu, 25 Aug 2011 20:54:15 -0700, Richard Knoppow wrote: I was taugh that correct usage and punctuation was important and that people would judge you by it. I think now that I was simply taught to be an intellectual snob. Anyone can be one, you don't need a lot of money or an impressive wardrobe. Snipped and bottom posted (just to annoy Garey... :) ). My mother was a school teacher, and we tended to play little grammar and punctuation games when I was young. Grammatic absurdities were a favorite target. That's part of it. When I went online with dialup BBSes here in the city back in the mid 80s (note the lack of apostrophe), most of the BBSes were either run by college professors, college students, or teenagers that were smart enough to know how to set up a BBS on an Apple II and had parents who were well-off enough to buy them one. In that crowd, poor grammar, syntax, and punctuation would get you ignored at best. To gain any credibility, you HAD to know how to present yourself and your ideas well. So there is something to that, you won't get very far in some online communities if your prose sux. IOW, if you type stupid, they think you are stupid As I get older, I've found that I have to proof my posts better. I don't always do as well as I think I should, but WTF. I'm not entirely sure why the apostrophe thing bugs me so much, but when people who have more education than I have and (presumably) make a lot more money than I do don't know the difference between plural and possessive, it just annoys me. The thing is, it seems to be everywhere these days. Other than that, my only other peeve is quote trimming, especially when people complain about a spam post and proceed to quote the whole spam in their complaint. But back to Drakes, since this is the Drake's list, after all. 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime. HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
